U.S. Pat. No. 4,711,934 discloses cationic paint binders which can be characterized through the schematic structure ##STR1## wherein E--is the moiety of an epoxy compound,
--PH--is the moiety of a phenol, PA1 A--is the moiety of an amine, and PA1 --DI--NCO is the moiety of a semi-blocked diisocyanate. PA1 R.sub.4 is a hydrogen atom or, when R.sub.1 is H, a hydrogen atom, or the radical --CH.sub.2 --N(R.sub.3)--CO--NH--R.sub.5, and PA1 R.sub.5 is the radical of a diisocyanate semi-blocked with a monofunctional compound,
Surprisingly, the products of the patent can be produced in a very simple manner and, upon protonation, provide water-dilutable paints with good applicational properties and, at a temperature as low as about 160.degree. C., provide self-crosslinked films. It has been found, however, that coatings based on such products on various corrosion tests, such as salt spray or cycle tests, do not give the high values particularly required by the automobile industry. Further, adhesion to a variety of PVC-substrates as are used in the automobile industry as car underbody protection or as sealing materials could be further improved.